CN112041697A - Positioning system - Google Patents

Abstract

A system for positioning objects on a surface waveguide is disclosed. Surface waveguides are made of one or more 1D lines and/or 2D waveguides comprising conductive elements arranged in a pattern. A transmitter with a known position can be coupled to a receiver, which is coupled to the surface waveguide. The location of the receiver can be determined, for example, by multi-location or signal strength indication. The conductive elements may be sprayed, stitched, or otherwise deposited onto surfaces such as substrates, sidewalks, or driveways. The described developments include the use of absorbers, protective layers, unidirectional emitters, contactless coupling, and various arrangements including frequency selective layers, in lattices, lattices, or anisotropic surfaces. Signal processing aspects and software embodiments are also described.

Description

GPS

technical field

This document relates to the field of digital data processing, and more particularly to localization methods and systems.

Background technique

Precisely locating objects or people in space can be a challenging task. Indoor positioning can be particularly difficult because broadcast signals from Global Navigation Satellite System (GNSS) satellites are often not available inside buildings.

Existing methods present limitations. For example, patent application US20160219549 entitled "SYSTEMS, METHODS AND DEVICES FORINDOOR POSITIONING USING WIFI" deals with time delays in the propagation of one or more Wi-Fi signals to determine position. Such methods may exhibit insufficient accuracy and reliability for specific uses (eg, detecting dead bodies dropped on the floor in a secure area or hospital, or detecting the abnormal presence of liquid on the floor). Such methods usually imply a delay or delay before detection.

Few existing methods are available that are suitable for both indoor and/or outdoor applications, which require accuracy, speed and reliability.

Therefore, there is a need for advanced methods and systems for indoor positioning and/or outdoor positioning.

SUMMARY OF THE INVENTION

Disclosed herein is a system for locating objects on a surface waveguide. Surface waveguides are made of one or more 1D wires and/or 2D waveguides comprising conductive elements arranged in a pattern. A transmitter (or receiver) with a known location can communicate with a receiver (or transmitter) that is coupled to the surface waveguide. The location of the receiver (or transmitter) can be determined, for example, by multi-location or signal strength indication. The conductive elements may be sprayed, stitched or otherwise deposited onto surfaces such as ground floors, sidewalks or driveways. The described developments include the use of absorbers, protective layers, unidirectional emitters, contactless coupling, and various arrangements including frequency selective layers, arrangements in lattices, trellis, or anisotropic surfaces. Signal processing aspects and software embodiments are also described.

Favorable embodiments of the present invention include, but are not limited to, precise positioning of objects (articles, such as road cars or small objects found on a table) or animals or people.

Description of drawings

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which like reference numerals refer to like elements, and in which:

Figure 1 shows an embodiment of the invention,

Figure 2 shows various embodiments of surface waveguides,

Figure 3 shows various embodiments of signal transmitters and surface coupled devices,

FIG. 4 illustrates some other aspects of the present disclosure.

Detailed ways

Definitions of terms are provided below.

"Location" or "Location" specifies the coordinates of the object/receiver in space. Location can be tracked or monitored over time.

A "coordinate system" is a system that uses one or more numbers or coordinates to uniquely determine the location of a point or other geometric element in space (eg, Euclidean space). Coordinates can use ordered tuples. Different coordinate systems can be used, including but not limited to number lines, Cartesian coordinate systems, polar coordinate systems, cylindrical and spherical coordinate systems, homogeneous coordinate systems, curvilinear coordinate systems, orthogonal coordinate systems, oblique coordinate systems, log polar Coordinate system, barycentric coordinate system, trilinear coordinate, etc.

"Surface" can designate a support surface in any structure (eg, the ground floor in a train). The term "surface" may designate a portion of a room, corridor, etc., which forms its lower closed surface and on which people walk. The term may also designate a support surface that extends horizontally throughout a building with multiple rooms, apartments, etc., and constitutes a level or stage in the structure. In particular, while using the singular form, multiple interconnected surfaces can be used (bridges providing electrical coupling can be created via/through walls or ceilings).

A "surface" according to the present invention may be one or more of the following: floor, ground, interior floor surface, bottom, area, cushion, carpet, parquet, walkway, basement, canvas, carpet, deck, Indoor floors, rugs, stages, wooden boards, cellars, slabs, etc.

A "surface" may include flat and/or non-flat portions or subregions. In other words, the surface according to the invention does not have to be completely flat. It can be horizontal, vertical (wall), angled, inclined, flat, curved, curved, twisted, bumpy, embossed, etc.

"Waveguide" designates a structure that guides waves (eg, electromagnetic waves) with minimal energy loss by confining expansion in one or two dimensions. A waveguide may be a hollow conductive metal tube used to carry high frequency radio waves. The geometry of the waveguide can vary. 1D (one-dimensional) waveguides confine energy in a one-dimensional fiber or channel. The frequency of the transmitted wave can also dictate the geometry and shape of the waveguide. For 1D waveguides, the width of the waveguide is typically of the same order of magnitude as the wavelength of the guided wave. Depending on the frequency, the waveguide may be constructed of conductive and/or dielectric materials. Waveguides can be used to transmit both power/energy and communication signals.

The present invention relates to "surface waveguides" (which utilize the "surface waveguide" properties). Surface waves (waves propagating in/on conductive surfaces) generally cannot couple to external plane waves. At optical frequencies, prism coupling can be used. A prism can be placed next to the surface, and the refractive index of the prism can be used to match the wave vector of the probe beam to that of the surface wave. At microwave frequencies, small probes can be used. A point source can emit all wave vectors, and a small antenna placed near the surface can couple to surface wave modes (in addition, the antenna geometry can be adjusted to differentiate polarizations). In TM (transverse magnetic) surface waves, the electric field forms loops that extend perpendicularly out of the surface. TM waves can be measured using a pair of small monopole antennas oriented perpendicular to the surface. The vertical electric field of the probe is coupled to the vertical electric field of the TM surface wave. In a TE (transverse electric) surface wave, the electric field is parallel to the surface. It can be measured with a pair of monopolar probes oriented parallel to the surface. The horizontal electric field of the antenna is coupled to the horizontal electric field of the TE wave. On flat metal plates, the measurement of TE waves produces no significant signal because any antenna that excites TE waves will short-circuit on the conductive surface.

Only on a specific textured surface, with its unusual surface impedance, is it possible to obtain a distinct TE transmission signal level. Embodiments of the present invention describe several types of specific surface waveguides and their use in indoor positioning.

Patterns or templates are identifiable rules (eg, repeating arrangements). The elements of the pattern repeat in a predictable way. A geometric pattern is a pattern formed from geometric shapes and typically repeats like wallpaper. Patterns include spirals, zigzags, waves, foam, tiling, cracks, and patterns created by the symmetry of rotation and reflection. Patterns can have basic mathematical structures. Visual patterns can be combined and repeated to form patterns.

Lattice specifies an arrangement of decorative criss-cross frames, crisscross slats, or other thin strips of material. A lattice, grid, or raster graph is a graph that is drawn to form regular tiles. A grille is a hollow frame composed of a criss-cross pattern of strips of building material. The design was created by crossing these strips to form a network. A lattice can be used as a truss structure (eg, a lattice girder bridge). A lattice beam is a beam in which the flanges are connected by a lattice mesh. The lattice corresponds to the symmetry group of discrete translational symmetry in n directions.

A treillage is an architectural structure, typically made of open frames or interwoven lattices or intersecting sheets of material. Trellis may also be referred to as panels and are usually made of interwoven sheets, such as attached to a fence or to the roof or exterior walls of a building.

In engineering, a truss is a structure that "consists of only dual-stressed members, where the members are organized such that the assembly as a whole appears as a single object". A "Dual Forced Member" is a structural assembly in which forces are applied to only two points.

Disclosed herein is a system for locating an object on a surface waveguide, comprising: one, two, three or more (depending on the embodiment) signal transmitters having known positions associated with the surface ( For example, embedded therein); the object is associated with a receiver configured to determine its position based on processing signals received from the signal transmitter through one or more waveguides embedded in the surface waveguide.

In some embodiments (eg, one transmitter, multiple receivers), the terms "transmitter" and "receiver" are interchangeable.

Surfaces can be assigned Surface Waveguides. Multiple configurations of such surfaces are described herein.

Signal transmitters are attached to the surface, acting as 2D waveguides. In some embodiments, the signal transmitter may be embedded in the surface. The term "embedded" may be replaced by "on" or "over" or "in" or "under". One or more signal transmitters may be arranged or disposed or placed on and/or over and/or within and/or under a surface (eg, a fabric embodiment). In some embodiments, at least one transmitter may be operably coupled to the surface (eg, a signal transmitter may be disposed in/on a wall of a room that includes the waveguide surface).

In an embodiment, the receiver includes a surface-coupled device configured to receive electromagnetic signals transmitted by the signal transmitter.

In some embodiments (eg, one transmitter, multiple receivers), the verb "receive" may be replaced by the verb "transmit."

In some embodiments, the coupling may be non-contact (ie, local modification or perturbation of the underlying electromagnetic field). In an embodiment, for example a coaxial probe may be used. In some embodiments, the coupling may utilize electrical contacts, such as with conductive threads (eg, shoelaces) that slide over the floor (for continuous contact) or electrical components for intermittent contact (eg, inserted into the heel of a shoe) or under the heel).

In one embodiment, the location of the receiver is determined by one or more of the following: multipoint positioning and/or trilateration and/or triangulation and/or received signal strength indication and/or fingerprint and/or or angle of arrival and/or flight time.

In some embodiments (eg, one transmitter, multiple receivers), the noun "receiver" may be replaced by the noun "transmitter".

In an embodiment, the position of the object/receiver with respect to the base station may be obtained by multi-point positioning (hyperbolic navigation or "TDOA") and/or trilateration and/or triangulation and/or received signal strength indication (RSSI) and/or Or fingerprint and/or Angle of Arrival (AoA) and/or Time of Flight (ToF) based techniques.

Multipoint positioning may be based on measurements of distance differences by broadcasting signals at known times to two base stations at known locations. Measuring the difference in distance between two stations can enable the determination of possible locations for drawing the hyperbola. To determine the exact location along this curve, a multipoint survey relies on multiple surveys: a second survey on a different pair of stations will result in a second curve that intersects the first. When the two curves are compared, a small number of possible positions are shown, resulting in a "fix". Advantageously, in the case of multipoint positioning, no common clock is required. Additionally or alternatively, trilateration can also be used. Trilateration uses absolute measurements of distance or time-of-flight at three or more locations. In geometry, trilateration is the process of determining the absolute or relative position of points by measuring distances using the geometric shapes of circles, spheres, or triangles. Additionally or alternatively, triangulation may be used. Triangulation uses measurements of absolute angles (the position of a point is determined by forming a triangle from a known point to it). Corner measurement specifies a combination of triangulation and trilateration.

In an embodiment, the receiver is locally associated with the GNSS receiver, wherein the receiver is further configured to encode and transmit the geographic location determined by the GNSS receiver via electromagnetic signals through the surface waveguide.

In an embodiment, the receiver is "locally associated" with the receiver (because it is physically attached to the GNSS receiver, eg, worn by the user or placed next to the shoe as a releasable extension).

The GNSS receiver may be configured to determine the signal-to-noise ratio and pseudorange. GNSS receivers determine user position, velocity and precise time ("PVT") by processing signals broadcast by satellites. The GNSS component can obtain SNR (which stands for Signal to Noise Ratio) and pseudorange. GNSS positions (if obtained and once transmitted) can be used to improve the accuracy of the positions of other objects. In other words, cooperating devices may include GNSS-enabled devices.

The processing and/or storage unit (for encoding, processing and storing satellite signals) may be local (eg, local memory or associated to an embedded computer) and/or remotely accessible (cloud computing, eg, configured to compute servers and/or external devices that are located and associated with the base station, such as located nearby).

In an embodiment, the transmitting base station may transmit GNSS-like signals into/into the surface.

In an embodiment, the system further includes a clock accessible by the receiver and the at least one signal transmitter.

In some embodiments, a reference clock or a synchronization clock may be required (eg, for time of arrival TOA or time difference to TDOA fix) or advantageously used (if optional), depending on the type of measurement. In some embodiments, a single clock may be shared since data communications may allow such clocks to be shared and accessed between cooperating devices (receivers and one or more base stations). In some embodiments, no clock is required (ie, for time-independent positioning techniques). In an embodiment, scheduling such as round-robin may be used (time slices or amounts of time may be predefined, eg, with associated transmit priorities). Other mechanisms can include voting mechanisms, distributed consensus in distributed systems, and variants of round-robin scheduling (weighted round-robin, deficit round-robin, multi-level queues, etc.).

In an embodiment, the surface waveguide is placed on a support surface, the support surface being one or more of the following: a ground floor, a sidewalk, a street, a transportation platform, a driveway, a bus lane, or an airport landing.

In an embodiment, the system further comprises one or more signal or electromagnetic wave absorbers.

In some embodiments, the surface may be associated with an electromagnetic absorber.

Radio waves can be at least partially absorbed (notched, attenuated). Electromagnetic absorbers may include materials specifically selected or designed to suppress or reduce reflection or transmission of electromagnetic radiation (e.g., dielectric in combination with metal plates spaced at specified intervals or wavelengths, with specific absorption frequencies, thicknesses, components, etc.) layout and material configuration). Resonant absorbers and/or broadband absorbers can be used.

Surface wave absorbers can avoid or minimize multipath. "Wave absorbers" can be placed appropriately to minimize multipath. In particular, absorbers can be placed at the edges or corners of the room (for global optimization of guided waves). In an embodiment, the wave absorber and waveguide are intimately mixed (for local optimization of guided waves).

In some embodiments, eg in combination with wave absorbers, wave junctions or bridges may be appropriately placed in the system to extend the surface to allow location (bridge from one room to another) to be determined.

In an embodiment, the surface further includes a protective layer.

Optionally, one or more protective layers may be added to protect the described combination of conductive layers. Such protection allows outdoor use. For example, the protective layer may be transparent and/or colored. The protective layer may include solar cells.

In an embodiment, at least one transmitter is unidirectional.

In an embodiment, the surface coupled device uses contactless coupling.

In an embodiment, the surface coupling device is inserted or otherwise embedded in a shoe or a tire of a vehicle.

In an embodiment, the system further includes a computer configured to process the time-determined positions of the plurality of objects.

In peer-to-peer (distributed model) implementations and/or centralized implementations, groups of cooperating devices may generate large amounts of data and may require additional computing power.

Figure 1 shows an embodiment of the present invention.

Figure 1 shows "base stations" or "signal transmitters" or "access points" (111, 112, and 113) disposed on and/or within surface 121 (eg, in room 122). The surface may comprise 1D (one-dimensional, eg wire) and/or 2D waveguides. One or more base stations emit electromagnetic (radio) waves. Object 101 associated with receiver 102 is located/positioned on surface 121 (eg, a user's shoe). The distances between objects 101/102 and different base stations (eg, 112) can be determined in different ways.

The figure also shows that surface 121 can be connected to a number of other surfaces, such as surface 199 (which is located in another room). For example, wires 198 may be used to connect between rooms.

In an embodiment, the "surface" or circuit board 121 includes a waveguide.

The waveguide can be 2D (two-dimensional) or include 2D regions. The waveguide can also be 1D (one-dimensional, eg a wire). Surfaces can be interconnected, for example via wires between rooms.

Within the same room, the surfaces can include 1D and/or 2D waveguides. In multiple rooms of a building, surfaces may be interconnected logically (with respect to positioning) and/or physically (eg, by electromagnetic bridges or wires interconnecting the multiple surfaces and/or rooms). Complex interconnection schemes can be used; for example, a portion of a surface in a first room can be interconnected with a portion of another surface in a second room.

In a particular embodiment, three base stations are used. One or more base stations may incorporate AC power plugs and receptacles (eg, "mains plug", "electrical plug", "plug top", "power outlet", "plug socket", "wall socket", "wall plug" Wait).

In an embodiment, two base stations are used (the measurements are then repeated over time, and the location can be determined by augmentation).

In an embodiment, a single base station (electromagnetic signal EM in the floor) is used, combined with two other 3D signals (ie elevation, height). According to such an embodiment, the receiver may then use two different modules (eg a module provided in the shoe and another part located eg in a smartphone).

In an embodiment, one transmitter and any number of receivers are used. Each receiver allows to determine its distance from the transmitter: by collecting three distances, external logic can determine the position of each receiver (the transmitter is located at the intersection of three circles with a radius equal to the corresponding distance). According to such an embodiment, the room may require minimal instrumentation. In some other embodiments, two signal transmitters supplemented by external information sources are used.

In an embodiment, one transmitter and one or two receivers are used. Each receiver allows its distance to the transmitter to be determined. By collecting one or two distances, external logic can combine other information to determine the location of each receiver (eg, one receiver is in a corner). According to such an embodiment, the room may advantageously require the installation of reduced instrumentation.

In an embodiment, a "peer-to-peer" system is implemented: both the roles of the transmitter and the receiver are supported by the same object. For example, object 101 may be a transmitter/receiver inserted into the heel of a shoe worn by a user located in the room. Where there are multiple users in the same room equipped with such objects, point-to-point negotiation can be handled (with or without centralized intelligence or logic circuits). Fleets may be heterogeneous (some objects may be transmitters/receivers, while others may only include receivers). In some embodiments, some transmitters have a fixed location, eg, inserted in the ground, while some other transmitters are movable. Such an embodiment advantageously reduces to a minimum the equipment required to operate the GPS; for example, a user's shoes (modified to include the present invention) walking on carpet (modified to include the present invention) may be sufficient for Realize indoor positioning.

Embodiments of the present invention may be combined with existing positioning systems, including machine vision, RFID tags, inertial systems, wireless communications, and the like. For example, however, the location or position of a person or object without any instrument according to the present invention can be indirectly determined or located if a reference point including the present invention can be tracked. For example, the child can be located if the accompanying parent wears shoes including the present invention and there is a Bluetooth™ connection between the devices worn by the parent and the child to establish relative positioning. In other words, prior knowledge of the geometry between objects or people helps to deduce position along measurements performed according to other techniques.

In some embodiments, a person or object with an instrument (according to the present invention) that is intermittently connected is located indirectly, eg, by combining information from other techniques as previously stated (eg, via methods such as short-range/ contactless networks such as range communication networks) and/or by processing the history of previous connections and/or by using more sophisticated data calculation and/or prediction algorithms (expected movements, etc.).

In an example of a point-to-point implementation, a shared clock may be used. The transmitter and/or receiver roles may be swapped, eg given an applied external heartbeat, or according to other timing schemes. Such an embodiment advantageously allows avoiding the need for any privileged roles and thus reduces possible vulnerabilities of the network (eg if a node is rendered unavailable). In an embodiment, the shared clock is organized and/or distributed by the surface itself. In an embodiment, scheduling such as round robin may be used (time slices or amounts of time may be predefined, eg, with associated transmit priorities). Other mechanisms could potentially include voting mechanisms, distributed consensus in distributed systems, and variants of round-robin scheduling (weighted round-robin, deficit round-robin, multi-level queues, etc.).

Figure 2 shows various embodiments of surface waveguides.

Disclosed herein are surface waveguides that are configured to direct electromagnetic signals emitted from one or more transmitters and are further configured to couple with one or more receivers placed on the surface waveguides, the receivers being positionable Determined by signal processing.

In an embodiment, the surface waveguide includes one or more one-dimensional line waveguides.

In an embodiment, the surface waveguide includes one or more two-dimensional (2D) waveguides.

In an embodiment, the two-dimensional waveguide includes conductive elements.

Surface waveguides may advantageously be at least partially coated with a dielectric material (better conductivity and signal capture).

In an embodiment, the surface waveguide may further include an electrical mass layer.

In an embodiment, the surface waveguide further comprises one or more vias (improved guiding) connecting the one or more conductive elements and the electrical mass layer.

In an embodiment, the surface waveguide includes two frequency selective layers that support transverse magnetic and transverse electrical modes, respectively, with the same phase velocity.

In an embodiment, the first layer includes gaps in a first direction and the second layer includes continuous conductive strips in a second orthogonal direction.

In an embodiment, the conductive elements are arranged in a pattern (modified or different wave guides).

In an embodiment, the pattern forms a lattice or trellis.

In an embodiment, the pattern is an irregular pattern and the surface waveguide is anisotropic.

In an embodiment, the conductive elements are painted and/or sprayed and/or burnt and/or deposited and/or coated and/or sewn and/or printed onto the support surface.

In an embodiment, the support surface is one or more of the following: a ground floor, a sidewalk, a street, a transportation platform, a driveway, a bus lane, or an airport landing.

In an embodiment, the location of the receiver is determinable by one or more of the following: multipoint positioning and/or trilateration and/or triangulation and/or received signal strength indication and/or Fingerprints and/or angle of arrival and/or time of flight.

Disclosed herein are multilayer surfaces comprising a plurality of surface waveguides according to any of the preceding embodiments, wherein each surface waveguide may be associated with a different emitter (eg, associated with a different frequency), and wherein each The surface waveguides are configured to be coupled with the same receiver (concurrent positioning system).

Surfaces (waveguides) manipulated in accordance with the present invention can be fabricated (eg, assembled, fabricated) in different ways. In one embodiment, the surface comprises or is made of ID (one-dimensional) wires in a (regular or irregular) grid or grid. In one embodiment, the surface comprises or is made of a two-dimensional (2D) waveguide. Two-dimensional (2D) embodiments can become increasingly complex. In a variant, only the conductive element 211 may be required (ie, the exemplified components 212 and 213 are not used). The conductive elements may be metallic. The shape and arrangement of the conductive elements can be varied and can influence, more precisely guide the propagation of electromagnetic waves. Such metal elements may be arranged on-site and/or off-site. They can be painted (eg, sprayed through a mask or without a mask) and/or burned (PCB boards, possibly flexible electronics) and/or deposited and/or coated and/or stitched and /or inserted and/or printed into/on pre-existing and/or specific support surfaces. Chemical reactions and/or mechanical processes can be used.

The pre-existing surface on which the conductive elements may be arranged may be local ground (eg, the floor of a room, asphalt of a road) and/or a pre-existing support surface (eg, carpet).

In a variant, the conductive elements 211 may be arranged above and/or below and/or within the dedicated layer 213 (acting as an electrical mass, thereby improving the 2D confinement of electromagnetic signals propagating in the surface). Layer 213 may be one or more of the following: carpet, tent pad, jacket, envelope, film, layer, sheet, blanket, layer, mask, screen, and the like. In some embodiments, metal element 211 may be placed over bottom layer 213 . In some embodiments, conductive (eg, metal) elements 211 may be placed under the bottom layer 213 . In some embodiments, portions of element 211 may be placed above bottom layer 213 and portions may be placed below bottom layer 213 .

In an embodiment, the surface 212 includes a conductive (eg, metal) element 211 (eg, a circuit board substrate) and a layer 213 (eg, a polyimide layer). The circuit boards can be pressed together, separated by layers of polyimide, which can form an insulator for the capacitor.

In an embodiment, layer 213 may be, for example, a carpet to which conductive elements 211 are attached during manufacture (such specific "instrumented" carpets may be packaged in rolls and may be further installed, cut, and optionally glued in the building's room). In another embodiment, the layer 213 may be a paint layer onto which the conductive elements may be further sprayed (a protective film may be applied later to prevent scratching and damage). In one embodiment, the conductive element may be part of the paint itself. In an embodiment, the layer 213 is asphalt of the road and the conductive elements are mechanically inserted. In a variant, the conductive elements are sprayed onto the road, optionally further protected by a deposit for protection (eg a glass layer).

In a variant, in addition to the conductive elements 211 and the electrical masses 213 , a plurality of through holes 212 can be arranged. Conductive elements (eg, formed as metal patches and placed at the top) may be connected to bottom layer 213 through metallized vias, and vice versa. Metallized vias can allow vertical connections between horizontal traces made from conductive elements on the surface. In some embodiments, the system includes vertical conductive vias, such as if very high impedance values are required, or to completely block surface waves.

Advantageously, this arrangement (with boundary conditions) prohibits some frequency bands. By engineering a surface, such as with specific textures on a conductive surface, its RF electromagnetic properties can be modified and/or affected. In cases where the period of the surface texture is significantly smaller than the wavelength, the structure can be characterized by one parameter: the surface impedance.

In an article titled "ELIMINATING SURFACECURRENTS WITH METALLO DIELECTRIC PHOTONIC CRYSTALS" published by Sievenpiper in the 1998 IEEE MTT-S Digest, it has been shown that some types of metal-dielectric photonic crystals can serve as engineered artificial metals, which Electromagnetic waves can be completely excluded (ie, the propagation of electromagnetic radiation through its entirety is prohibited) and surface currents can be supported. By engineering the geometry of the surface, especially by arranging the metal islands that are incorporated into the dielectric lattice, a band gap can be built (ie, over a range of frequencies) for surface currents that are associated with most of the band gap overlap (but without unwanted surface waves), thereby providing a ground plane for antenna applications. This effect can only be achieved by arranging thin skins of photonic crystal structures on a regular metal surface.

In this arrangement, surface waves can occur at the interface between two dissimilar materials (eg, metal and free space). Electromagnetic waves can be trapped at interfaces and can decay exponentially into surrounding materials.

By properly configuring the arrangement of the conductive elements 211, the substrate layer 213 and the vias 212, the electromagnetic signals can be precisely controlled, thereby enabling advantageous use for indoor positioning.

In an embodiment, the geometry of the surface used by the system according to the invention comprises a corrugated metal surface, wherein the corrugations can be folded into lumped circuit elements and distributed in a lattice. In some embodiments, its periodicity may advantageously be significantly inferior to the free space wavelength.

In an embodiment, the geometry of the surface used by the system according to the invention comprises a metal sheet or a corrugated metal sheet covered with small bumps. Uneven surfaces can be used. Therefore, by applying a periodic texture (eg, a lattice of small raised protrusions), surface waves can be advantageously eliminated from the metal surface in a limited frequency band. In an embodiment, the corrugated surface is or comprises a flat metal plate from which a series of vertical grooves can be cut. In an embodiment, the grooves are narrow so that many of these grooves can fit within one wavelength across the slab. In embodiments, the surface may be a periodic two-dimensional or three-dimensional dielectric metal or metal-dielectric structure.

In some embodiments, the conductive patch or grid 211 may include one or more of the following: copper, gold, conductive ink or paint. Dielectric substrate 212 may include one or more of the following: wood, varnished cloth, paper, non-conductive paint. The conductive layer 213 may include a metal patch made of conductive paint. The surface may include one or more of these layers.

Other geometric shapes or textured surfaces are also possible. A certain geometry of a particular surface waveguide can support both TM (transverse magnetic) and TE (transverse electrical) modes with the same phase velocity. A first type of surface wave guide may consist of two frequency selective surfaces (layers with TM mode and TE mode). Such frequency selective surfaces may be of loop type or wire grid type. The second type of surface wave guide may also include at least two layers (the top layer includes gaps in a first direction and continuous conductive strips in a second orthogonal direction).

Regarding topology, the frequency-selective surface may include multiple unit-cells. The mode dominated by the unit cell geometry can be a TE mode (eg, square patch, square loop, or Jerusalem cross). Gaps between adjacent conductive patches or wires can advantageously create a dominant capacitive response at low frequencies. Cell geometries with dominant TM modes may include wire grid structures and/or annular groove structures (their surface impedance is induced).

In an embodiment, the top layer may include square loops and the bottom layer may include wire grids. For the sides of the square/grid, the physical dimensions of the loop line cell geometry may range, eg, 3.5mm, the layers are placed 0.5mm from each other, and the loop/wire width may range from 0.225mm to 0.25mm.

In embodiments, the bilayers may include more complex arrangements (having shapes such as bow ties or hexagonal cells).

In complex embodiments, the geometry may vary in space (ie, irregular unit cells). In Jiyeon Lee and Daniel F. Sievenpiper's article "Patterning Technique for Generating Arbitrary Anisotropic Impedance Surfaces" (IEEE 2016), several patterning methods have been shown to determine the range of cell size, shape and orientation, including smooth variation and height anisotropic The opposite sex impedance surface. Thus, anisotropic impedance surfaces can be used, in particular for controlling surface waves, scattering, conformal antennas and waveguides. Their electromagnetic properties can be defined by the thickness of the substrate and the capacitance between the patches, which together determine the efficient surface impedance. Varying element size and shape allows impedance to be controlled.

Anisotropic surfaces may include square and/or circular patches with slices rotated to any angle, and/or other patterns restricted to square lattices, as well as lower symmetry cells that cannot be arranged in any pattern. Multiple patterns can be obtained (variable cell shape, gradient of impedance, direction of change, etc.).

Additional geometric shapes and patterns are described.

In an embodiment, the surface is flat.

In an embodiment, the surface is substantially (locally) planar, ie, sufficiently close to flat that the associated error is minimal. Such embodiments allow indoor positioning (eg, apartments, offices, commercial centers, etc.) where the thickness of the 2D waveguide can be sufficiently controlled.

In some embodiments, the thickness of the 2D waveguide may vary. The geometry map of the coated/distributed waveguide can then be determined/calibrated and further considered.

In some embodiments, multiple waveguides may be used, possibly with different geometries. The geometry of the waveguide can vary. A waveguide according to the present invention may be a 1D or 2D waveguide (ie, in two dimensions). 2D waveguides can be distributed in space (ie, coated), but a grid of waveguides is also envisaged.

The geometry of the waveguide may include one or more shapes and/or one or more patterns.

Shape can be one or more of the following: Circle, Square, Rectangle, Butterfly, Spiral (2D, Archimedes, Cornu, Fermat, Hyperbolic, Logarithmic, Fibonacci deed, etc.).

Patterns can be symmetrical or asymmetrical. Patterns can include one or more of the following: trees, fractal structures (for example, to increase contact surfaces), spirals, manifolds, 30 meanders, waves, dunes, bubbles, foam, cracks, spots, stripes , a grid, or a combination thereof (of the aforementioned geometries). The pattern may comprise a checkerboard arrangement (a pattern formed by repeating tiles over the entire surface). A tile set may include wax-like cells (eg, wax-like cells in a honeycomb). Shards can overlap. Patterns can use regularly repeating three-dimensional arrays (eg, crystal structures, Bravais lattices). Other forms or geometries may include, but are not limited to, arrays, tiles, walkways, mesh structures, and the like. Fabric patterns are also possible (eg, end-to-end, needle stripes, rain patterns, burlap, etc.). Surfaces may include one or more of the following: minimal surfaces, ruled surfaces, non-orientable surfaces, quadratic surfaces, pseudospherical surfaces, or algebraic surfaces. Some patterns may be controllable (eg, configurable at the beginning or dynamically, evolving over time, etc.).

In an embodiment, the surface includes a repeating pattern (or periodic structure).

Advantageously, the pattern and/or periodic structure is as minimal as possible, preferably less than half the wavelength. In some embodiments, the pattern/decoration can be less than 10% of the surface coupled device.

The selection of the wavelength of the signal emitted by the signal transmitter depends on a number of parameters. In an embodiment, the wavelength may be a first-order function of the accuracy required by the intended use of the system (eg, a storage warehouse with strict accuracy requirements). The wavelength may also depend on safety regulations (but it may also minimize the radiation field present above the surface).

The size of the lattice advantageously allows slowing down the propagation time of electromagnetic waves and/or improving accuracy/precision. In an embodiment, the accuracy of the envisaged use of the described system is used as input in order to influence the propagation velocity of electromagnetic waves and in order to further determine or constrain the size or geometry of the waveguide surface (or waveguides in/in the surface).

In an embodiment, multiple frequencies are used, advantageously eliminating or minimizing errors.

In an embodiment, the conductive layer includes a plurality of sublayers. The conductive layer may include a plurality of small islands or "islands" (disconnected regions) of the conductive layer that may be logically bonded together (logically by software) and/or physically bonded together by strips, bridges, or the like.

The pattern or periodic structure may comprise one or more of the following: a grid and/or a grid and/or a trellis and/or a lattice.

In some embodiments, the surface comprising the waveguide is permanent, while in some other embodiments it is temporary (eg, a movable conductive grid).

In an embodiment, the surface is multi-layered to advantageously allow multiple base stations to be addressed in parallel.

In some embodiments, the surface is divided into different parts, each part having different properties (eg, different "resolutions" with respect to positioning).

One or more waveguides (assemblies of conductive elements and/or mass layers and/or vias) manipulated by the present invention may be painted and/or painted in (pre-existing, dedicated, modified, etc.) support surfaces. /or coating and/or sewing and/or depositing.

In an embodiment, the waveguide is coated. Electromagnetic waves can propagate into specific substances (eg, "metasurfaces" or surfaces coated with dielectrics). In an embodiment, the surface is at least partially coated with a dielectric material of known properties. In an embodiment, the surface comprises a polyvinyl chloride or vinyl ("tarpaulin") backing or a carpet that may be coated with a dielectric layer.

In an embodiment, the waveguide is printed. Capacitively coupled structures can be obtained by using printed circuit board technology. Circuit boards can be stacked and bonded together to form 3-D periodic structures.

In an embodiment, the waveguides are assembled. In an embodiment, the facing metal elements are separated by a dielectric layer. The substrate may be, for example, a microwave circuit board dielectric material. The polyimide layer can be a separate circuit board. Metal patches on each adjacent board can be aligned to form metal/polyimide/metal capacitors. Boundaries can be obtained under pressure with adhesives (eg, novolac butyral).

In an embodiment, the waveguide is painted (eg, sprayed). In some embodiments, the surface is sprayed with a conductive material. For example, roads or sidewalks can be sprayed and/or coated with conductive materials to form 2D waveguides (thickness may or may not be controllable).

In embodiments, the 2D waveguides may be coated and/or painted and/or sprayed and/or stitched and/or otherwise deposited onto existing surfaces (eg, sidewalks, etc.) in combination.

Advantageously, in some embodiments, the bottom layer may not require modification: additional conductive layers may be provided. For example, the ground floor of a conference center may be painted, sprayed, or otherwise coated or deposited with a conductive layer (eg, ink deposition or ink printing with conductive particles).

In some embodiments, the waveguides are stitched (ie, locally, such as in a particular carpet). For example, the surface may be woven (or knitted, felted, braided, or braided) at least partially (combinations of sets of yarns or threads may be interwoven to form a fabric surface).

Figure 3 shows an example of an embodiment of a signal transmitter and surface coupling device.

Figure 3 shows an embodiment illustrating a variation of a signal transmitter (or base station) and/or surface and/or coupling device or mechanism.

The figure includes an object 101 (eg, a shoe or tire) associated with a receiver associated with a surface coupling device 102 . The surface-coupled device can then acquire signals propagating in the surface 121, such as signals transmitted by a plurality of base stations (301, 302).

Electromagnetic signals can be transmitted both through signal transmitters (which can be omnidirectional or isotropic, but can also be directional) and/or through surfaces (specific embodiments of waveguides can guide signals in specific ways) Revise.

In one example, base station 301 is omnidirectional (transmitting isotropically). For example, such a base station could be hidden in the center of a room being monitored.

In another example, base station 302 is directional. Such base stations can be placed in the corners of the room.

In other embodiments, the structure of the surface can affect the propagation of electromagnetic signals. For example, anisotropic surface wave guides can be advantageously used.

Variations of surface coupled devices are now described.

In an embodiment, the object/receiver 101/102 comprises a "surface coupled device" or "coupler" or "connector". Such a device may establish an operational/operable electrical (ie electromagnetic) contact/coupling between the receiver 102 or base station (111, 112 and 113) and the surface/2D waveguide 121.

Various embodiments are possible for such surface coupled devices. Different types of coupling are possible. Electrical conduction can be used (eg, through hardwired connections, resistance, or natural conductors). Electromagnetic induction can be used (eg, inductive coupling, magnetic coupling, capacitive coupling, evanescent wave coupling).

Surface coupling can be achieved through wires, resistors or common terminations such as binding posts or metal bonds.

A vertical (or horizontal) monopole probe antenna can be used: the probe can couple to the vertical (or horizontal) electric field of the surface wave.

Different coupling mechanisms can be used. Mechanical mechanisms involving springs or other components can optimize the surface and/or duration of contact. For example, a shoe may include a deformable contact surface, which provides advantages for improving the reliability of electrical/electromagnetic contacts. In such an embodiment, the coupling mechanism may contact the convex shape.

In some embodiments, the surface coupling device is embedded in one or more parts of one (or both) of the user's shoes (modified shoes). For example, the components of the surface-coupling device may be distributed in one or more of the following: upper, heel, toe, upper, welt, top, etc. (even if deliberately maintained in contact with the ground shoelaces). The welt and/or heel may include conductive elements in contact with the ground.

In some embodiments, the surface coupling device is configured to be associated with (attachable to) a standard shoe. For example, a surface coupling mechanism can be inserted into a hole drilled in the heel. In some cases, modifications to the shoes are not even required since the surface coupling device can be linked (either a releasable attachment or a non-releasable attachment) to one or more shoes.

Other embodiments relate to wheels or tires of transport vehicles (eg, tires may include conductive threads or components that are in contact with the ground at least from time to time). The contact sequence can also lead to an assessment of the displacement velocity (eg, by calibration) given the geometry of the surface-coupled device. In some embodiments, the contact between the surface and the surface-coupled device is permanent. In some other embodiments, the contacting is intermittent or periodic.

Changes in duration and/or location allow further determination of specific events, such as a person or object falling on the ground or in a flood.

In some embodiments, the surface-coupled device is coupled to the surface without any physical contact ("non-contact" mode). For example, electromagnetic induction can be used.

FIG. 4 illustrates some other aspects of the present disclosure.

Systems and methods in accordance with the present invention may be further "enhanced": additional positioning systems may be agreed to increase the accuracy and/or reliability of positioning (eg, outdoor use of GNSS positioning that may utilize nearby available and accessible cooperating devices ).

In an embodiment, the determined position will be further communicated to an external system for possible correction.

In an embodiment, the receiver is part of a computer or IoT device or the like (eg, a smartphone worn by the user). One or more computers may be accessed locally and/or remotely to obtain or provide computing capabilities 411 and memory 412 (eg, storage devices).

Object/receiver 100 may communicate with other systems 413 or 414 (eg, servers providing floor plans, IoT devices, etc., to GNSS signals or PVT, and other sensors such as inertial sensors and an odometer) to communicate (eg, in a two-way manner).

Further embodiments are now described.

Described herein is a system for locating an object on a surface waveguide, comprising: one, two or three signal transmitters with known positions associated with the surface; an object associated with a receiver, the The receiver is configured to determine its position from the signal received from the signal transmitter via one or more waveguides embedded in the surface waveguide.

In one embodiment, the system includes three "signal transmitters" (triangulation or trilateration requires three points). In fact, the signal transmitters may be of different nature: in some cases one or even both of these signal transmitters (in the surface waveguides according to the invention "actively" emit signals) may be used by other types of devices complement or even replace. Indeed, in one embodiment, the system includes two (active) signal transmitters, the third transmitter being replaced by the provision of "external information" (eg, which may be transmitted in a beacon (or device or terminal) A predetermined geographic location or location, the beacon may provide location information in response to a query, or broadcast its location information without a request). For example, a beacon, device or terminal may be or be included in a smartphone, or even a smartphone that is mobile (ie, worn by the user), which may transmit or otherwise broadcast its location on demand. In some embodiments, two of the three location points are associated with such "external" information (two smartphones broadcasting their locations can help locate the fourth location point).

The location can be determined locally and/or remotely (in the latter case means communication capability) from signals received from at least three signal transmitters. In one embodiment, the object includes circuitry configured to calculate the position of the object from the three received signals (this calculation can advantageously be performed with little or short delay). In one embodiment, the object is associated with a server or computer configured to calculate the position from the three signals (thus, the calculation can also be performed quickly, or even at a later time).

In one embodiment, the receiver includes a surface-coupled device configured to receive electromagnetic signals transmitted by the signal transmitter.

In one embodiment, the location of the receiver is determined by one or more of the following: multipoint positioning and/or trilateration and/or triangulation and/or received signal strength indication and/or fingerprint and/or or angle of arrival and/or flight time.

In one embodiment, a receiver (local and/or remote) is associated with a GNSS receiver, and the receiver is further configured to encode and/or transmit the geographic location determined by the GNSS receiver via electromagnetic signals through surface waveguides . Emissions can be delayed, ie at a later time.

In one embodiment, the system further includes a clock accessible by the receiver and the at least one signal transmitter.

In one embodiment, the surface waveguides are placed on a support surface that is one or more of the following: a ground floor, a sidewalk, a street, a transportation platform, a driveway, a bus lane, or an airport landing.

In one embodiment, the system further includes one or more electromagnetic signal or electromagnetic wave absorbers. In an embodiment, the surface further includes a protective layer. In one embodiment, at least one signal transmitter is unidirectional.

In one embodiment, the at least one signal transmitter is a smartphone configured to transmit its corresponding location.

In one embodiment, the surface coupled device uses contactless coupling.

In one embodiment, the surface coupling device is embedded in (or associated with) the object. Surface coupling can be embedded in materials such as plastic, rubber, wood, etc. Surface couplings may be embedded or inserted into or associated with or attached to objects such as shoes or cloth (during the manufacturing process or by the user, etc.). Things can be connected devices (eg, IoT devices). The object may be a tire of a vehicle.

In one embodiment, the system further comprises (or is associated with/associated with) a processing unit configured to determine the position of the object (once, or repeatedly over time). In some embodiments, the position of the object may be monitored over time, ie movement may be tracked. The evolution of the position associated with a given object over time can be compared to a predefined scene, and events can be determined. For example, a modified shoe worn by an elderly person may cause a predefined temporal pattern to be expected on the floor. Interruption of such patterns (or anomalies thereof) may lead to determining the probability of a fall on the floor (eg, further potentially raising an alarm for disabled persons or employees working in the hazardous area). Multiple objects can be tracked in parallel. On sidewalks, where specific surveillance is required, for example, the flow of people can be monitored and people traveling against the current can be detected. In a warehouse, specific paths of items can be expected and abnormal routes can be detected.

In one embodiment, the frequency of the transmitted signal is selected within a range of predefined frequencies associated with the object to be detected. In some embodiments, some prior knowledge about the objects to be detected or tracked may be available. In some cases, the frequency of the signal may be adjusted to better detect (eg, more accurately and reliably) some specific objects. For example, modified shoes worn by the elderly can be better detected or tracked if one or more predefined and specific signal frequencies are used. One or more frequencies may be tuned (defined) according to the "fingerprint" and/or position or velocity of the object under consideration on the floor, etc.

In some other embodiments, a receiver associated with the object is not even required. For example, a frequency of 2,45 GHz may be suitable for detecting large amounts of liquid (eg water) on the floor. Such embodiments may be advantageous in trucks, in safe areas or in trains, for example.

It may be noted that, in some embodiments, precise determination of the object's position is not required, and some examples are more related to the time associated with the event. Determination of such events (eg, the fall of a person, a path followed by a machine in a warehouse) derived from a collection of locations over time can be achieved by measuring fluctuations in time of flight and/or signal power. Such information (ie, no location information) may be necessary and sufficient to determine the occurrence of an event in the monitored area.

In one embodiment, the frequency of the transmitted signal is variable over time. In some embodiments, the frequency of the signal is configurable. In particular, it can evolve over time to act as a "radar". For example, to detect liquid flooding in warehouses, certain frequencies can facilitate detection. After the initial detection, additional frequencies can be used to further improve the detection. The frequency can also vary depending on possible scenarios (object or person falling on the floor, risk of flooding, etc.).

In one embodiment, the transmit signal includes multiple signals of different frequencies. In some embodiments, the signal is not limited to a single frequency: a multi-frequency approach allows efficient "scanning" of the ground, particularly by avoiding or minimizing multi-path or signal perturbations (eg, a function of the carrier signal). Advantageously, the use of multiple frequencies may improve the accuracy of the positioning and/or its reliability. It can also distinguish objects if tracked in parallel.

Described herein are surface waveguides configured to direct electromagnetic signals emitted from one or more transmitters, the surface waveguides being further configured to couple with one or more receivers associated with the surface waveguides, the receivers' The position can be determined through signal processing.

In one embodiment, the surface waveguide includes one or more one-dimensional line waveguides. In one embodiment, the surface waveguide includes one or more two-dimensional waveguides. In one embodiment, the one or more two-dimensional waveguides include conductive elements. In one embodiment, the surface waveguide includes an electrical mass layer. In one embodiment, the surface waveguide includes one or more vias connecting the one or more conductive elements to/with the electrical mass layer. In one embodiment, the surface waveguide includes two frequency selective layers that respectively support a transverse magnetic mode and a transverse electric mode (eg, have the same phase velocity). In one embodiment, the first layer of the surface waveguide includes gaps in a first direction, and the second layer includes continuous conductive strips in a second (eg, substantially) orthogonal direction. In one embodiment, the conductive elements are arranged in a pattern. In one embodiment, the pattern forms a lattice or trellis. In one embodiment, the pattern is an irregular pattern and the surface waveguide is anisotropic. In one embodiment, the conductive elements are painted and/or sprayed and/or burnt and/or deposited and/or coated and/or sewn and/or printed onto the support surface. In one embodiment, the support surface is one or more of the following: a ground floor, a sidewalk, a street, a transportation platform, a driveway, a bus lane, or an airport landing. In one embodiment, the location of the receiver is determined or determinable by one or more of the following: multipoint positioning and/or trilateration and/or triangulation and/or received signal strength indication and/or fingerprints and/or angle of arrival and/or time of flight.

Described herein is a surface comprising a plurality of surface waveguides according to the preceding paragraphs, wherein each surface waveguide is configured to be associated with a different transmitter, and wherein each surface waveguide is configured to be coupled to the same receiver.

Accordingly, the examples disclosed in this specification are merely illustrative of some embodiments of the invention. They do not in any way limit the scope of the described invention, which is defined by the appended claims.

Claims (15)

1. A system (100) for positioning an object (101) on a surface waveguide, comprising:

-at least two signal emitters (111, 112) associated with the surface having known positions;

-the object (101) is associated with a receiver (102), the receiver (102) being configured to determine its position from signals received from the at least two signal transmitters through one or more waveguides embedded in the surface waveguides.

2. The system of claim 1, wherein the receiver comprises a surface coupling device configured to receive the electromagnetic signal transmitted by the signal transmitter.

3. The system of any preceding claim, wherein the location of the receiver is determined by one or more of: multilateration and/or trilateration and/or triangulation and/or received signal strength indication and/or fingerprint and/or angle of arrival and/or time of flight.

4. The system of claim 1, wherein the receiver is associated with a GNSS receiver, wherein the receiver is further configured to encode and/or emit the geographic position determined by the GNSS receiver via electromagnetic signals passing through the surface waveguide.

5. The system of any preceding claim, further comprising: a clock accessible by the receiver and at least one signal transmitter.

6. The system of any preceding claim, wherein the surface waveguide is placed on a support surface, the support surface being one or more of: bottom floor, sidewalk, street, transportation platform, driveway, bus lane, or airport landing lane.

7. The system of any preceding claim, further comprising: one or more electromagnetic signal or electromagnetic wave absorbers.

8. A system according to any preceding claim, wherein at least one signal emitter is unidirectional.

9. The system of any preceding claim, wherein at least one signal transmitter is a smartphone configured to transmit its respective location.

10. The system of any preceding claim, wherein the surface coupling device uses non-contact coupling.

11. The system of any preceding claim, wherein the surface coupling device is embedded in or associated with an object.

12. The system of any preceding claim, further comprising or being associated with a processing unit configured to determine a likely position of the object over time.

13. The system of any preceding claim, wherein the frequency of the transmitted signal is selected in a range of predefined frequencies associated with the object to be detected.

14. A system according to any preceding claim, wherein the frequency of the transmitted signal varies over time.

15. A system according to any preceding claim, wherein the transmitted signal comprises a plurality of signals of different frequencies.

Images